Popular consensus today largely holds that everyone who can should go to college; this has been a more-or-less dominant public opinion for decades now. But what if it isn’t really true—what if higher education is actually less applicable to the masses than we believe?

“A lifetime of experience,” writes Bryan Caplan in a lengthy essay at The Atlantic, “plus a quarter century of reading and reflection, has convinced me that [higher education] is a big waste of time and money.”

Caplan, a tenured professor at George Mason University in Virginia, notes in fairness that “the earnings premium for college graduates has rocketed to 73 percent—that is, those with a bachelor’s degree earn, on average, 73 percent more than those who have only a high-school diploma, up from about 50 percent in the late 1970s.”

Yet “the key issue,” he points out, “isn’t whether college pays, but why. The simple, popular answer is that schools teach students useful job skills. But this dodges puzzling questions.”

Caplan notes that, throughout the entirety of their educational career, “students spend thousands of hours studying subjects irrelevant to the modern labor market,” such as trigonometry, physics, and art. “Why do English classes focus on literature and poetry instead of business and technical writing?” Caplan asks.

“The labor market doesn’t pay you for the useless subjects you master,” Caplan points out, “it pays you for the preexisting traits you signal by mastering them. This is not a fringe idea.”

“As a society, we continue to push ever larger numbers of students into ever higher levels of education. The main effect is not better jobs or greater skill levels, but a credentialist arms race.”

Lest I be misinterpreted, I emphatically affirm that education confers some marketable skills, namely literacy and numeracy. Nonetheless, I believe that signaling accounts for at least half of college’s financial reward, and probably more.Most of the salary payoff for college comes from crossing the graduation finish line. Suppose you drop out after a year. You’ll receive a salary bump compared with someone who’s attended no college, but it won’t be anywhere near 25 percent of the salary premium you’d get for a four-year degree. Similarly, the premium for sophomore year is nowhere near 50 percent of the return on a bachelor’s degree, and the premium for junior year is nowhere near 75 percent of that return. Indeed, in the average study, senior year of college brings more than twice the pay increase of freshman, sophomore, and junior years combined. Unless colleges delay job training until the very end, signaling is practically the only explanation. This in turn implies a mountain of wasted resources—time and money that would be better spent preparing students for the jobs they’re likely to do.

The conventional view—that education pays because students learn—assumes that the typical student acquires, and retains, a lot of knowledge. She doesn’t. Teachers often lament summer learning loss: Students know less at the end of summer than they did at the beginning. But summer learning loss is only a special case of the problem of fade-out: Human beings have trouble retaining knowledge they rarely use. Of course, some college graduates use what they’ve learned and thus hold on to it—engineers and other quantitative types, for example, retain a lot of math. But when we measure what the average college graduate recalls years later, the results are discouraging, to say the least.

“Would I advise an academically well-prepared 18-year-old to skip college because she won’t learn much of value?” Caplan asks. Absolutely not. Studying irrelevancies for the next four years will impress future employers and raise her income potential.”

Just the same, Caplan writes: “Civilized societies revolve around education now, but there is a better—indeed, more civilized—way. If everyone had a college degree, the result would be not great jobs for all, but runaway credential inflation. Trying to spread success with education spreads education but not success.”